Energy transfers between and in organisms

Question 1

describe light dependent reactions in photosynthesis

Answer 1

1. light excites electrons in the chlorophyll
2. electrons pass down the ETC
3. electrons lose energy as they pass along the ETC in thylakoids
4. this causes phosphorylation of ATP and reduces NADP
5. photolysis of water

Question 2

describe light independent reactions in photosynthesis

Answer 2

1. RuBP + CO2
2. forms GP
3. ATP and NADPH from LDR used to reduce GP to TP
4. 2 TP used to make organic substances
5. 10 TP used to regenerate RuBP

Question 3

Describe the parts of the chloroplast and some of their functions

Answer 3

1. Ribosomes
2. Starch grains
3. Stroma- site of LIR and contains enzymes for LIR
4. Granum- increases SA for LDR in thylakoids
5. Thylakoids- site of LDR
6. double membrane
7. circular DNA

Question 4

define chemiosmosis

Answer 4

synthesis of ATP coupled with electron transfer and proton movement

Question 5

Describe glycolysis

Answer 5

1. phosphorylation of glucose to glucose phosphate using ATP
2. production of 2 TP
3. oxidation of 2 TP to produce 4ATP and 2NADH and 2 pyruvate
4. location of glycolysis is in cytoplasm

Question 6

describe the Krebs cycle

Answer 6

1. one ATP per cycle
2. in the metrix of mitochondria
3. decarboxylation of 6C
4. removal of hydrogen by NAD and FAD of 6C
5. substrate level phosphorylation of other carbon compounds produced
6. FADH2 and NADH produced- these molecules pass electrons to electron transport chain
7. 4C regenerated

Question 7

describe the link reaction

Answer 7

1. pyruvate is oxidised to acetate producing NADH
   2.acetate combines with CoA enzyme to produce acetyl CoA

Question 8

describe oxidative phosphorylation

Answer 8

1. H+ pumped across inner membrane
2. creates concentration gradient
3. electrons transferred between carriers
4. chemiosmosis
5. H+ pass down concentration gradient
6. through ATPase complex into matrix of mitochondria
7. oxygen is final acceptor forming water

Question 9

Structure of mitochondria

Answer 9

1. outer membrane
2. inner membrane
3. cristae (folded version of inner membrane)
4. matrix
5. inter membrane space
6. ribosomes
7. ATP synthase
8. loop of DNA

Question 10

explain the importance of oxygen being the final electron acceptor

Answer 10

without oxygen the electron transport chain would not function as NAD+ would not be regenerated

Question 11

describe anaerobic respiration

Answer 11

1. glycolysis
2. pyruvate reduces to ethanol or lactate by NADH
   3.NAD produced used again in glycolysis
3. lactate can convert back to pyruvate to convert to glycogen

Question 12

Define biomass

Answer 12

can be measured in term of carbon or dry mass of tissue per given area.

Question 13

Calorimetry

Answer 13

estimates the chemical energy store in dry biomass

Question 14

Gross primary production

Answer 14

the chemical energy store in plant biomass in a given area or volume

Question 15

net primary production

Answer 15

chemical energy store in plant biomass ager respiratory losses to the environment have been taken into account

Question 16

NPP=

Answer 16

GPP-R

Question 17

primary and secondary productivity

Answer 17

rate or primary or secondary production. it is a measured as biomass in given are in a given time

Question 18

nitrogen fixation

Answer 18

conversion of atmospheric nitrogen gas into nitrogen containing compounds by nitrogen fixing bacteria

Question 19

ammonification

Answer 19

production of ammonia when saprobiontic microorganisms feed on nitrogen containing compounds

Question 20

nitrification

Answer 20

conversion of ammonium ions to nitrite ions which are then oxidised to nitrate ions

Question 21

denitrification

Answer 21

conversion of nitrate ions to nitrogen gas by denitrifying bacteria

Question 22

phosphorous cycle

Answer 22

1. weathering causes phosphate ions to be released from rocks to water and soil
2. ions taken up by plant roots or algae from the water
3. consumers eat the plants
4. phosphate ions eventually found in waste products and dead organisms to be decomposed by saporbionts

Question 23

leeching

Answer 23

process in which ions dissolved in water and are carried from soil end up in rivers and lakes

Question 24

eutrophication

Answer 24

algae growth

Question 25

Mycorrhizae

Answer 25

facilitates the uptake of water and inorganic ions by plants. it has a large surface area and acts as a sponge to hold the ions.

Question 26

saprobionts

Answer 26

decompose waste and dead matter by extracellular digestion making inorganic ions available for other organisms